Installation, Operation & Application Guide LIA265-1 Group: WSHP Supercedes: LIA217 Date: 12-19-08 Programmable Electronic Thermostat 2 Heat/2 Cool, 7-Day Programmable, Hardwired Part No.
Table of Contents Specifications . . . . . . . . . . . . . . . . . . . . . . . Important Safety Information . . . . . . . . . . Package Contents/Tools Required . . . . . . . To Remove Existing Thermostat . . . . . . . . To Install Thermostat . . . . . . . . . . . . . . . . Remote Sensor Installation (Optional) . . . . Terminal Designator Descriptions . . . . . . Wiring Diagrams . . . . . . . . . . . . . . . . . . . .
Specifications Electrical rating: • 24 VAC/VDC (18-30 VAC/VDC) • 1 amp maximum per terminal • 4 amp maximum total load Temperature control range: 45°F to 90°F (7°C to 32°C) Accuracy: ± 1°F (± 0.5°C) System configurations: 2-stage heat, 2-stage cool Terminations: -C, +R, W1, Y1, W2, Y2, G, S1, S2 Important Safety Information WARNING!: Always turn off power at the main power supply before installing, cleaning, or removing thermostat.
To Remove Existing Thermostat ELECTRICAL SHOCK HAZARD – Turn off power at the main service panel by removing the fuse or switching the appropriate circuit breaker to the OFF position before removing the existing thermostat. 1. Turn off power to the heating and cooling system by removing the fuse or switching the appropriate circuit breaker off. 2. Remove cover of old thermostat. This should expose the wires. 3. Label the existing wires with the enclosed wire labels before removing wires. 4.
To Install Thermostat (continued) 2. To remove cover, insert and twist a coin or screwdriver in the slots on the sides of the thermostat. 3. Put thermostat base against the wall where you plan to mount it (Be sure wires will feed through the wire opening in the base of the thermostat). 4. Mark the placement of the mounting holes. 5. Set thermostat base and cover away from working area. 6. Using a 3/16” drill bit, drill holes in the places you have marked for mounting. 7.
Remote Sensor Installation (Optional) Requires McQuay Remote Sensor Part Number 667720401 1. Remove cover from remote sensor housing. 2. Select an appropriate location for mounting the remote sensor. 3. Mount remote sensor unit using hardware provided. 4. Install two strand shielded wire between remote sensor and thermostat. Shielded wire must be used. Do not run remote sensor wire in conduit with other wires.
Terminal Designator Descriptions Wiring Diagrams McQUAY SINGLE CIRCUIT ELECTRONIC THERMOSTAT G O W G W Y F E L U A P V + 2 1 1 R C Mark IV Board Low Voltage Terminal Board -C +R W1 Y1 W2 Y2
Mark IV Board Circuit 1 Low Voltage Terminal Board O W G W Y F E L U A P V + 2 1 1 R C Mark IV Board Circuit 2 Low Voltage Terminal Board O W G W Y F E L U A P V + 2 1 1 R C McQUAY DUAL CIRCUIT ELECTRONIC THERMOSTAT -C +R W1 Y1 W2 Y2 G
Configuration Mode The configuration mode is used to set the SC3801 to match your heating/cooling system. The SC3801 functions with heat pump, air conditioning, gas, oil, or electric heat systems. 1. To enter the configuration mode, simultaneously hold down the and SC3801 is in OFF mode. 2. Press the or button to change settings within each screen. 3. Press the button to advance to the next screen. Note: The button will return you to the previous screen. 4.
Configuration Mode Settings (continued) 4. Temperature scale (F or C) – Choose Fahrenheit or Celsius. Press the or button to select. Press the button to advance to the next screen. 5. Stage 1 Differential (1°F to 3°F) (1°C to 2°C) – Set the number of degrees between your “turn on” temperature and your “setpoint” temperature. Press the or button to set differential value. Press the button to advance to the next screen. 6.
Configuration Mode Settings (continued) 10. Fan OFF Delay – HEAT cycle (0-240 seconds) – Time fan is delayed turning OFF after heat cycle. For no delay, set to 0:00. Note: This appears only for heat pump or electric heat systems. Press the or button to set delay. CAUTION!: Changing from the default of 0:00 may permanently damage your system. Press the button to advance to the next screen. 11. Fan ON Delay – COOL cycle (0-120 seconds) – Time fan is delayed turning ON at start of cool cycle.
Configuration Mode Settings (continued) 15. Status indicator (0, 1, 2) – Choose when status indicator LED (green, red) illuminates. 0 = Status indicator never on 1 = Status indicator on with first stage 2 = Status indicator on with second stage or button to select. Press the Press the button to advance to the next screen. 16. Lockout (0°F to 8°F, NITE, COOL-HEAT) – Select the number of degrees set temperature can be changed during keypad lockout or select to lockout during NITE period only.
Testing the Thermostat Once the thermostat is installed, it should be thoroughly tested. CAUTION!: Do not energize the air conditioning system when the outdoor temperature is below 50 degrees. It can result in equipment damage or personal injury. Cool Test 1. 2. 3. 4. Press mode button until cool mode screen is displayed. Adjust set temperature so it is 5 degrees below room temperature. Air conditioning should come on within a few seconds.
Mode of Operation The McQuay Programmable Thermostat is an auto changeover, two stage heat, two stage cool thermostat. The thermostat activates a heating appliance when the room temperature is below the set heat temperature (by the differential temperature). The red status indicator may come on with first or second stage, depending on configuration. When it drops another two degrees, the second stage (auxiliary) heat is activated. The heating is staged off when the room temperature increases.
Operating Modes Program Overview These are the possible operating modes for the McQuay Programmable Thermostat OFF Mode In this mode, the thermostat will not turn on the heating or cooling devices. Note 1: The indoor fan can be turned on manually in every operating mode by sliding the Auto/On switch to ON. Note 2: To enter Programming Fan Only Mode, press the button once. Only the indoor fan will operate during that period if it is activated in the program setup.
Operating Mode (continued) Program Mode In this mode, the program function is on, and the thermostat will automatically be controlled by the set program. Program mode can function with Heat mode, Cool mode, Cool and Heat mode or OFF mode (for Programmable fan option only). Press the button to enter and exit program mode. Program Mode Hold The program schedule can be overridden by changing the set temperature ( or ). After 2 hours, the program schedule will automatically be resumed.
Programming Program Overview The McQuay Programmable Thermostat has four periods (MORN, DAY, EVE, NITE) that are customizable for each day of the week. Each period will have a start time, heat temperature, cool temperature and programmable fan. The thermostat monitors the day and time, while maintaining the specific conditions you have chosen for each period in your program. 1. Verify thermostat is in non-programmable mode (use the button to exit prog mode). 2.
Programming (continued) • Set time is displayed or button to change set time. 9. Press the 10. Press the button to advance to the next screen. Note: Transitions required after 11:59 PM must be programmed in the next day’s MORN period. • Heat temperature is displayed (50°F to 90°F) or button to adjust heat set temperature. 11. Press the 12. Press the button to advance to the next screen. • Cool temperature is displayed (45°F to 85°F) or button to adjust cool set temperature. 13. Press the 14.
Simpleset® Programming Simpleset programming is a convenient method of programming the thermostat. Once the entire Monday (Day 1) schedule is set, Simpleset® programming will copy the Monday schedule to every day of the week. After the complete Monday schedule is set (see Programming on Page 16), you are at the Day 2 screen: button once. Day 1 screen displays. 1. Press the button for 2 seconds. 2. Press the • The days of the week will count down from 7 to 1 and this will lock the settings into memory.
Factory Preprogramming The McQuay Programmable Thermostat comes preprogrammed with the following schedule: MONDAY thru SUNDAY * Programmable fan option MORN HEAT COOL FAN* 6:00 AM 70°F 78°F ON/OFF DAY HEAT COOL FAN* 8:00 AM 62°F 85°F ON/OFF EVE HEAT COOL FAN* 6:00 PM 70°F 78°F ON/OFF NITE HEAT COOL FAN* 10:00 PM 62°F 82°F ON/OFF Personal Program Schedule Use the following personal program schedule to record your settings: MONDAY 1 * Programmable fan option TUESDAY 2 WEDNESDAY 3 18 MORN DAY
Personal Program Schedule (continued) THURSDAY 4 FRIDAY 5 SATURDAY 6 SUNDAY 7 MORN DAY EVE NITE HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* MORN DAY EVE NITE HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* MORN DAY EVE NITE HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* MORN DAY EVE NITE HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HEAT COOL FAN* ON/OFF HE
McQuay 7-Day Programmable Thermostat Factory Defaults NOTE: Following are the factory default settings for the McQuay thermostat: 1. Heat Pump OFF 2. Reversing Valve O/B N/A 3. Heat Electric ON 4. F/C F 5. Differential Stage 1 1 6. Differential Stage 2 2 7. Deadband 5 8. Staged Off Outputs ON 9. Heat Fan Delay on 0:00 10. Heat Fan Delay off 0:00 11. Cool Fan Delay on 0:00 12. Cool Fan Delay off 0:00 13. Cycles Per Hour d 14. Auxiliary Delay on N/A 15.
Troubleshooting Symptom Remedy No display Check for 24 VAC/VDC at thermostat; display is blank when 24 VAC/VDC is not present System fan does not come on properly Verify wiring is correct, check electric heat setup in configuration (see “Configuration Mode,” Page 7) Program schedule activates at the wrong time Check time (AM/PM) set on thermostat (see “Setting the Time,” Page 14) Thermostat turns on and off too frequently Adjust temperature differential (see “Differential,” Configuration Mode Setti
McQuay Training and Development Now that you have made an investment in modern, efficient McQuay equipment, its care should be a high priority. For training information on all McQuay HVAC products, please visit us at www.mcquay.com and click on training, or call 540-248-9646 and ask for the Training Department. Warranty All McQuay equipment is sold pursuant to its standard terms and conditions of sale, including Limited Product Warranty. Consult your local McQuay Representative for warranty details.
